Combinatorial method to optimize oxygen diffusion of (La1-xSrx)1-yCoO3 for SOFC cathodes
University of Delaware
Environmental issues paired with increased concern over energy security have made a need for energy efficient and non-carbon fueled power. This study has set the foundation for a novel way to choose materials and material compositions with optimal oxygen diffusion properties for cathodes in solid oxide fuel cells (SOFCs). SOFCs are one of the most promising types of fuel cells, being able to generate high efficiency stationary power. SOFCs can run on both hydrogen and hydrocarbon fuels such as natural gas. The ability to use multiple fuel types makes SOFCs ideal for the transition from a fossil fuel based system to a greener hydrogen economy. While SOFCs have been widely studied, there has been no specific standards for their cathode material (other than that they have a perovskite crystal structure). The major function of the cathode is to conduct electrons and provide oxygen ions to the electrolyte. This thesis has laid out a quick and efficient method by which the oxygen diffusion properties of a library of perovskite materials can be tested. This thesis utilized sputtering to create a thin film with varying compositions along the same substrate. Secondary Ion Mass Spectrometry (SIMS) was used to characterize the composition of the films and ensure that a variety of compositions were present on the substrate. This study focused on (La1-x Srx)1-yCoO3 however the method described would be valid for any perovskite material. Furthermore, while this research was done mainly to develop a way to test materials for fuel cell use, perovskites have been shown to have a wide variety of applications which allows this study to be relevant to other areas of research.